Methods and systems for automatic body-contouring imaging

ABSTRACT

Methods and systems for imaging a patient using an imaging system is provided. The method includes rotating a detector about a patient, detecting a predetermined distance of the detector from the patient, and automatically moving the detector to within a predetermined range of distance from the patient based on the detected distance.

BACKGROUND OF THE INVENTION

This invention relates generally to imaging systems, and moreparticularly to methods and apparatus for performing automaticbody-contouring imaging.

Diagnostic nuclear imaging is used to study radionuclide distribution ina subject, such as a patient. Typically, one or moreradiopharmaceuticals or radioisotopes are injected into the subject.Gamma camera detector heads, typically including a collimator, areplaced adjacent to a surface of the subject to monitor and recordemitted radiation. At least some known gamma camera detector heads arerotated around the subject to monitor the emitted radiation from aplurality of directions. The monitored radiation data from the pluralityof directions is reconstructed into a three dimensional imagerepresentation of the radiopharmaceutical distribution within thesubject.

Generally, the resolution of a gamma camera degrades with increasingdistance between the imaged organ and the detector. Therefore, it isdesirable to place the gamma camera as close as possible to the patientto facilitate minimizing the loss of resolution. At least some knownimaging systems use non-circular orbits, such as oval or ellipticalorbits to facilitate maintaining the detectors positioned close to thepatient during a scan. However, a standard elliptical or oval shapedorbit may not follow the body contour of a patient as closely aspossible.

BRIEF DESCRIPTION OF THE INVENTION

In one embodiment, a method of imaging a patient using an imaging systemis provided. The method includes rotating a detector about a patient,detecting a predetermined distance of the detector from the patient, andautomatically moving the detector to within a predetermined range ofdistance from the patient based on the detected distance.

In another embodiment, an imaging system for performing automaticbody-contouring is provided. The system includes a gantry with a patientbore therethrough, a rotor rotatably coupled to the gantry wherein therotor is configured to rotate about a longitudinal axis of the bore andwherein the rotor includes a transaxial movement assembly coupled to therotor, and at least one detector revolvably coupled to the transaxialmovement assembly, each at least one detector configured to revolveabout an axis that is parallel to the longitudinal axis of the bore, thetransaxial movement assembly is configured to translate each at leastone detector in a transverse plane of rotation of the at least onedetector.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevation view of a nuclear medicine imaging system inaccordance with an exemplary embodiment of the present invention;

FIG. 2 is a side elevation view of the nuclear medicine imaging systemshown in FIG. 1;

FIG. 3 is a front elevation view of the nuclear medicine imaging systemshown in FIG. 1 provided in an H-mode configuration;

FIG. 4 is a front elevation view of the nuclear medicine imaging systemshown in FIG. 1 provided in an L-mode configuration;

FIG. 5 is a front elevation view of another embodiment of the nuclearmedicine imaging system shown in FIG. 1 provided for an L-modeconfiguration;

FIG. 6 is a front elevation view of the nuclear medicine imaging systemshown in FIG. 1 in an exemplary one of a plurality of scan positions;

FIG. 7 is a side elevation view of the nuclear medicine imaging systemshown in FIG. 6;

FIG. 8 is a front elevation view of gamma cameras oriented in an L-modeconfiguration in a first exemplary scan position in accordance with anembodiment of the present invention; and

FIG. 9 is a table of sensor conditions that are used to control theautomatic body-contouring method in accordance with an exemplaryembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a front elevation view of a nuclear medicine imaging system 10in accordance with an exemplary embodiment of the present invention.FIG. 2 is a side elevation view of nuclear medicine imaging system 10shown in FIG. 1. System 10 includes a gantry 12 with a bore 14therethrough. A longitudinal axis 16 of bore 14 is orientedsubstantially perpendicular to gantry 12. In the exemplary embodiment,bore 14 is circular and extends from a front side 18 of gantry 12 to abackside 20 of gantry 12. Gantry 12 includes a foot portion 22 extendingorthogonally from a lower end 24 of gantry 12. Foot portion 22 is sizedto provide gantry 12 with a stable platform such that a center ofgravity of gantry 12 remains located within a footprint 26 of gantry 12.

A rotor 28 is rotatably coupled to gantry 12 adjacent to and/or withinbore 14. Rotor 28 may include an annular portion coupled to an innersurface 32 of bore 14. Annular portion extends axially toward backside20, at least partially into bore 14 and extends axially toward frontside 18 to a mounting ring 34 of gantry 12. Rotor 28 is rotatable withrespect to gantry 12 using, for example, a chain and sprocket drivecoupled to a motor (not shown) internal to gantry 12, a rack and pinionconfiguration, and/or a worm and toothed gear arrangement. Rotor 28 maybe rotatable in a clockwise (CW) direction 36 and a counter clockwise(CCW) direction 38 (as observed from a detector side of gantry 12), ormay be rotatable in only one of directions 36 and 38 using slip ringsand/or other wireless power and communication paths to transmitelectrical power and communication and data signals between rotor 28 andgantry 12. Mounting ring 34 is fixedly coupled to annular portion 30,such that annular portion 30 and mounting ring 34 rotate together withrespect to gantry 12. A first brace 40 and a second brace 42 may befixedly coupled to mounting ring 34 substantially parallel with respectto each other and oriented along diametrically opposed, generallytangential positions along mounting ring 34.

A lateral frame 44 is translatably coupled to brace 40 and brace 42through a first leg 46 and a second leg 48. A first end 50 of first leg46 and a first end 52 of second leg 48 are coupled together through afirst cross leg 54 and a second end 56 of first leg 46 and a second end58 of second leg 48 are coupled together through a second cross leg 60.Lateral frame 44 is translatable through, for example, a screw drive,hydraulic and/or pneumatic piston or other linear actuator coupledbetween legs 46 and 48, and first and second braces 40 and 42,respectively. The extent of lateral translation of lateral frame 44 maybe limited to prevent an inner periphery 61 of lateral frame 44 fromapproaching longitudinal axis 16.

A first radial member 62 is translatably coupled to cross legs 54 and60. A second radial member 64 is translatably coupled to cross legs 54and 60 in an opposed orientation to first radial member 62. First radialmember 62 and second radial member 64 are independently translatablewith respect to each other. Specifically, first radial member 62 istranslatable in a Radial-1 out direction 66 and a Radial-1 in direction67 concurrently with second radial member 64 being translatable in aRadial-2 in direction 68 and a Radial-2 out direction 69.

A base member 70 of first radial member 62 includes a pivot joint 72 anda base member 74 of second radial member 64 includes a pivot joint 76. Aradiation detector, such as a gamma camera 78 may be rotatably coupledto pivot joint 72 and a radiation detector, such as a gamma camera 80may be rotatably coupled to pivot joint 76. Pivot joint 72 permits gammacamera 78 to rotate about a longitudinal axis 82 of pivot joint 72 andpivot joint 76 permits gamma camera 80 to rotate about a longitudinalaxis 84 of pivot joint 76. Gamma cameras 78 and 80 may be rotatedmanually and fixed in place before each imaging scan, or may be rotatedautomatically during any portion of an imaging scan using an actuator(not shown). Gamma cameras 78 and 80 may be fixed during an imagingscan. In the exemplary embodiment, gamma cameras 78 and 80 may each beconfigured to rotate approximately forty-five degrees with respect toalignment with legs 46 and 48, respectively, in direction 36 anddirection 38. In an alternative embodiment, gamma cameras 78 and 80 mayeach be configured to rotate approximately ninety degrees in direction36 and direction 38.

Lateral frame 44, first radial member 62, and second radial member 64together form a transaxial movement assembly 86 that permits a rotationof gamma cameras 78 and 80 to be non-symmetric about longitudinal axis16. Transaxial movement assembly 86 permits movement of cameras 78 and80 to any position within the x, y plane during rotation of rotor 28 orwith rotor 28 maintained in a viewing position.

FIG. 3 is a front elevation view of nuclear medicine imaging system 10(shown in FIG. 1) provided in an H-mode configuration 300. In H-modeconfiguration 300, gamma cameras 78 and 80 are oriented at zero degreeswith respect to base members 70 and 74, respectively. Gamma cameras 78and 80 have a plurality of degrees of freedom of movement with respectto longitudinal axis 16. Rotor 28 is rotatable in directions 36 and 38,lateral frame 44 is translatable in a lateral out direction 302 and alateral in direction 304, first radial member 62 and second radialmember 64 are independently translatable in directions 66, 67, 68 and69, and gamma cameras 78 and 80 are rotatable about respective pivotjoints 72 and 76.

FIG. 4 is a front elevation view of nuclear medicine imaging system 10(shown in FIG. 1) provided in an L-mode configuration 400. In L-modeconfiguration 400, nuclear medicine imaging system 10 may be used for acardiac imaging scan wherein the gamma cameras are oriented orthogonallywith respect to each other. Such orientation facilitates completing aone hundred eighty-degree data set collection by rotating gamma cameras78 and 80 less then approximately one hundred eighty degrees aboutlongitudinal axis 16.

FIG. 5 is a front elevation view of nuclear medicine imaging system 10(shown in FIG. 1) provided in an L-mode configuration 400. Imagingsystem 10 includes a first proximity sensor system 500 associated withgamma camera 78 and a second proximity sensor system 502 associated withgamma camera 80. In the exemplary embodiment, each proximity sensorsystem 500 and 502 includes three sensor elements. In alternativeembodiments, proximity sensor systems 500 and 502 may include more orless than three sensor elements. A pressure sensitive safety device 504of each proximity sensor system 500 and 502 may be configured todeactivate automatic control of moving parts of imaging system 10, forexample rotor 28, lateral frame 44, first radial member 62 and secondradial member 64, and the rotation of gamma cameras 78 and 80 aboutpivot joint 72 and pivot joint 76, respectively, when pressure sensitivesafety device 504 contacts a subject (not shown in FIG. 5) beingscanned. After pressure sensitive safety device 504 detects contact withthe subject or other object, system 10 stops all moving parts of system10. Thereafter, control of the moving parts may be restricted to manualcontrol and motion that may bring gamma camera 78 nearer to the subjectbeing scanned may be restricted, even in manual control, until contactbetween pressure sensitive safety device 504 and the subject iscorrected.

A near proximity sensor 506 may be configured to stop the motion ofmoving parts in the direction toward the subject. In the exemplaryembodiment, near proximity sensor 506 is a row of light emitting diodes(LED) and photo-diodes extending along opposite edges of the face ofgamma cameras 78 and 80 that extend approximately one centimeter (cm)from pressure sensitive safety device 504. A far proximity sensor 508may be configured to stop the motion of moving parts away from thesubject. In the exemplary embodiment, near proximity sensor 506 and farproximity sensor 508 define a optimum distance range 509 to facilitateoperation of gamma cameras 78 and 80. In the exemplary embodiment, farproximity sensor 508 is a row of LEDs and photo-diodes extending alongopposite edges of the face of gamma cameras 78 and 80 that extendapproximately two centimeters from pressure sensitive safety device 504.In an automatic body-contouring mode of operation, the movement ofmoving parts in a direction away from the subject is not stopped orrestricted by near proximity sensor 506 and the movement of moving partsin a direction toward the subject is not stopped or restricted by farproximity sensor 508. Proximity sensor system 502 is configuredsimilarly to proximity sensor system 500.

FIG. 6 is a front elevation view of nuclear medicine imaging system 10(shown in FIG. 1) in an exemplary one of a plurality of scan positions600. Imaging system 10 includes a patient table 602 upon which a subjectto be scanned 604, for example a human patient, may be positioned.Subject 604 is generally positioned such that a region of interest 606,for example, a heart, is substantially aligned with longitudinal axis16. To facilitate maintaining gamma cameras 78 and 80 in relatively nearproximity to region of interest 606, patient table 602 may be configuredto be moved in a table up direction 608 and a table down direction 610with respect to gantry 12. Position 600 is illustrated with gammacameras 78 and 80 oriented in L-mode configuration 400 and rotor 28rotated in direction 36. As illustrated, none of the sensor elements ofproximity sensor systems 500 and 502 are close enough to subject 604 tobe actuated. Movement of patient table 602 may be subject to controlsand restrictions similar to the moving parts of system 10 such that whenpressure sensitive safety device 504 is actuated, motion of patienttable 602 may be stopped and only permitted to move in a direction thatmoves subject 604 away from gamma cameras 78 and 80 using manual controland automatic control may be suspended.

During an imaging scan, for example, but not limited to a SPECT imagingscan, gamma cameras 78 and 80 may be controlled to rotate about theouter periphery of subject 604. The rotation may be controlled bycontrolling the rotation of rotor 28 and is generally controlled toprovide step movement of approximately three degrees from one imagingposition to the next. Accordingly, subject 604 may be viewed by gammacameras 78 and 80 from a plurality of imaging positions extending, forexample, one hundred eighty degrees, three hundred sixty degrees, or incontinuous rotation about axis 16.

Specifically, when a three hundred sixty degree scan of subject 604 isperformed, gamma cameras 78 and 80 may be set in H-mode configuration300 (shown in FIG. 3) and rotor 28 is controlled to scan one hundredeighty degrees about subject 604. To utilize automatic body-contouringof subject 604 during a scan in H-mode configuration 300, patient table602 may be substantially centered within bore 14 and maintained in suchposition during the scan. Lateral frame 44 may be positioned to amaximum extent of travel in lateral in direction 304, and Radial 1 andRadial 2 are used independently to facilitate achieving an optimalproximity of gamma cameras 78 and 80 with respect to subject 604.

Proximity sensor systems 500 and 502 detect the position of each gammacamera 78 and 80, respectively, with respect to subject 604 during thescan. Table 1 below illustrates the actions of the automaticbody-contouring method for each possible state of near proximity sensor506 and far proximity sensor 508 for each of proximity sensor systems500 and 502. TABLE 1 Near Far proximity proximity State sensor 506sensor 508 Action Near Blocked Blocked Move respective radial memberproximity out OK Not blocked Blocked Do not move Far Not blocked Notblocked Move respective radial member proximity in Error Blocked Notblocked Stop all motion, Report “error”

For example, both of near proximity sensor 506 and far proximity sensor508 for gamma camera 78 and/or gamma camera 80 being blocked indicatesto system 10 that the respective gamma camera 78 and/or 80 is in nearproximity with respect to subject 604. System 10 controls the respectivefirst radial member 62 or second radial member 64 to move in therespective Radial-1 out direction 66 and Radial-2 out direction 69. Astate of near proximity sensor 506 and far proximity sensor 508, inwhich neither near proximity sensor 506 nor far proximity sensor 508 areblocked indicates to system 10 that respective gamma camera 78 and/or 80is in far proximity with respect to subject 604. System 10 then controlsthe respective first radial member 62 or second radial member 64 to movein the respective Radial-1 in direction 67 and Radial-2 in direction 68.A state in which near proximity sensor 506 is not blocked and farproximity sensor 508 is blocked indicates to system 10 that therespective gamma camera 78 and 80 are positioned within distance range509 from subject 604. System 10 then may begin data collection fromgamma cameras 78 and 80 from the view to which rotor 28 is rotated.

FIG. 7 is a side elevation view of nuclear medicine imaging system 10(shown in FIG. 6). Patient table 602 also may be configured to be movedin a direction parallel to longitudinal axis 16 such as a table indirection 612 and a table out direction 614 with respect to gantry 12.

FIG. 8 is a front elevation view of nuclear medicine imaging system 10(shown in FIG. 1) provided in L-mode configuration 400. In the exemplaryembodiment, gamma cameras 78 and 80 are configured to pivotindependently and first radial member 62 and second radial member 64 areconfigured to translate in and out independently. A reference axis 802is selected to point away from foot portion 22 and pass throughlongitudinal axis 16. Positions of rotor 28 rotation from axis 802 maybe referenced from reference axis 802. The rotation of rotor 28 may bedivided into a plurality of sectors for providing input to the automaticbody-contouring method. The method then may modify its output withrespect to the position of rotor 28. It should be noted that thedivision of the rotor position to sectors may be divided in other thanninety-degree sections and may be other than symmetric sections. Thesectors include a rotor on right sector 804, a rotor on left sector 806,a rotor above sector 808, and a rotor below sector 810.

The plurality of degrees of freedom of movement permitted by system 10allows the automatic body-contouring method to control three independentmotions in L-mode configuration 400. Table up direction 608, table downdirection 610, lateral out direction 302, lateral in direction 304,Radial-1 out direction 66, Radial-1 in direction 67, Radial-2 indirection 68, and Radial-2 out direction 69 may be controlledindependently with respect to each other. Movement of first radialmember 62 and second radial member 64 in combination moves gamma cameras78 and 80 in a direction that is perpendicular to the movement in thelateral in or lateral out direction. For example, gamma cameras 78 and80 may be moved sideways right by combining Radial-1 in direction 67 andRadial-2 out direction 69. Similarly, gamma cameras 78 and 80 may bemoved sideways left by combining Radial-1 out direction 66, and Radial-2in direction 68. Table up direction 608 and table down direction 610 maybe used only when at least one of lateral movement and radial movementhas reached a travel limit. Limiting table motion to a minimum amountnecessary to accomplish automatic body-contouring is provided, forexample, for patient comfort during a scan. The motions further can becombined to perform motion of gamma cameras 78 and 80 that are parallelto the face of one of gamma cameras 78 and 80. For example, equal ratemotion in lateral out direction 302 in combination with sideways rightmovement results in the face of gamma camera 78 remaining atsubstantially the same distance from subject 604 while gamma camera 80moves away from subject 604. This motion may be referred to as, gammacamera 80—Away. Similarly, lateral in direction 304 and a sideways leftmovement in combination may be referred to as gamma camera 78—towards.Similar motions may be combined to define a gamma camera 78 away andtowards movement.

Sensor systems 500 and 502 indications for each respective gamma cameramay be summarized as shown in Table 2 below. TABLE 2 Near Far proximityproximity State sensor 506 sensor 508 Indication Action Near BlockedBlocked Near proximity Move respective proximity radial member out OKNot blocked Blocked Best proximity Do not move Far Not blocked Notblocked Far proximity Move respective proximity radial member in ErrorBlocked Not blocked Error Stop all motion, Report “error” Error Any AnyError Pressure Stop all motion, Sensitive Safety Device 504 Report“error” Activated

When any of sensors 506, 508, or pressure sensitive safety device 504indicates “Error”, movement stops and only motion away from subject 604is permitted. Each motion axis includes a limit switch (not shown),indicating an end of travel (except for the rotation of rotor 28). Forexample, the limit switches associated with travel in Radial-1 in andout directions 66 and 67, and Radial-2 in and out directions 68 and 69will limit the sideways motion described above.

The automatic body-contouring method also may include a hierarchy ofmotions, for example, when at least one of gamma cameras 78 and 80 is innear proximity, the automatic body-contouring method initiates a motionthat attempts to move the gamma camera to an OK state wherein the faceof the gamma camera is within distance range 509 with respect to subject604. If a travel limit is reached while attempting to move the gammacamera into the OK state, the automatic body-contouring method initiatesa motion that attempts to move patient table 602 to a position thatpositions the gamma camera into the OK state. If at least one of gammacameras 78 and 80 is in far proximity (and the other gamma camera is notin near proximity), the automatic body-contouring method initiates amotion that attempts to move the gamma camera to an OK state. If atravel limit is reached while attempting to move the gamma camera intothe OK state, the automatic body-contouring method initiates a motionthat attempts to move patient table 602 to a position that positions thegamma camera into the OK state. If both gamma cameras 78 and 80 are inan OK state, the automatic body-contouring method does not initiatemotion to move gamma cameras 78 and 80 with respect to subject 604.

If any of any of sensors 506, 508, or pressure sensitive safety device504 are in an “Error” state, or travel limits have been reached, suchthat no motion is permitted, the automatic body-contouring method stopsall motion (including rotor rotation) and an alarm, such as an audibleor visual alarm, may be activated. During any movements, moving gammacameras 78 and 80 away from subject 604, for example, due to a gammacamera being in a near proximity position with respect to subject 604,takes priority over moving gamma cameras 78 and 80 towards subject 604,for example, due to a gamma camera being in a far proximity positionwith respect to subject 604.

FIG. 9 is a table 900 of sensor conditions that are used to control theautomatic body-contouring method. Table 900 includes a line referencenumber column 902 that identifies a set of indications from the sensorsof system 10 and a corresponding action command that is transmitted bythe automatic body-contouring method to control the speed and directionof the moving parts of system 10. Table 900 may be stored in a look-uptable in a memory of a motion controller portion (not shown) of system10 that receives indications of the proximity of gamma cameras 78 and 80to subject 604 and processes instructions to transmit commands thatcontrol the moving parts of system 10. Table 900 also includes, a column904, a column 906, a column 908 and a column 910 that each identify astate of sensor system 500, sensor system 502, the rotor positionencoder, and the travel limit switches, respectively. A column 912identifies the automatic body-contouring method action for movement ofgamma cameras 78 and 80, and a column 914 identifies the automaticbody-contouring method action for movement of patient table 602 for therespective states of the sensors. For example, line 1 of table 900illustrates the state wherein both sensor systems 500 and 502 indicatethat gamma cameras 78 and 80 are within distance range 509 from subject604. Rotor position is in a DON'T CARE state and the travel limits arealso in a DON'T CARE state. For this set of states, the automaticbody-contouring method will not attempt to move gamma cameras 78 and 80or table 602. As another example, line 4 indicates a set of stateswherein gamma camera 78 is within distance range 509 from subject 604,gamma camera 80 is in near proximity to subject 604, rotor position isin a DON'T CARE state and there are no travel limit switches activated.Under these conditions, the automatic body-contouring method initiatesmovement commands that move gamma camera 80 away from subject 604, anddoes not move table 602. Other lines of table 900 illustrate the outputof the automatic body-contouring method for various combinations ofinputs from sensor system 500, sensor system 502, the rotor positionencoder, and the travel limit switches. The rotation of rotor 28 from ascanning position to a next scanning position may cause any of thevarious inputs to change between scanning positions, such that gammacameras 78 and 80 circumscribe a path extending from subject 604 that isa distance away from subject 604 that corresponds to the settings ofnear proximity sensor 506 and far proximity sensor 508.

During continuous rotation of rotor 28, for example, when a continuousscan mode is selected, the automatic body-contouring method continuouslycontrols the movement of the moving parts of system 10, includingblocking the motion of rotor 28. For example, when a “step and shoot”scan mode is selected, rotor 28 rotates a predetermined number ofdegrees between each view position, for example, approximately onedegree to approximately four degrees, and stops rotation for apredetermined period, such as, approximately five seconds toapproximately thirty seconds, or for a predetermined number of gammacamera counts, to acquire data from a view.

In one embodiment, system 10 controls movement of first radial member 62or second radial member 64 and lateral frame 44 to initiate movementaway from subject 604 during rotation of rotor 28. When the rotationstops, the automatic body-contouring method may then permit the movementof first radial member 62, second radial member 64 and lateral frame 44towards subject 604 to achieve a best proximity position and stop forthe duration of the view acquisition. In a further embodiment, when therotation is stopped, the automatic body-contouring method may beconfigured to move gamma cameras 78 and 80 in only the away directionssuch that gamma cameras 78 and 80 do not follow the breathing of subject604, but will maintain best proximity for the inhale patient posture.

System 10 also may include position encoders (not shown) for each ofrotor 28, lateral frame 44, first radial member 62 or second radialmember 64, pivot joints 72 and 76, and patient table 602. The automaticbody-contouring method may transmit gamma cameras 78 and 80configuration and position based on the encoders for each degree offreedom to an acquisition processor (not shown) within system 10 orlocated remotely. Gamma camera 78 and 80 configuration and position maybe used to determine a relative direction of detected photons tocoordinates of subject 604. For example, in one embodiment, gamma camera78 and 80 configuration and position is transmitted to the acquisitionprocessor periodically, for example, every ten milliseconds. In analternative embodiment, only gamma camera 78 and 80 configuration andposition changes are transmitted. In another embodiment, patient table602 position may be programmed for a predetermined location depending ona type of scan to be performed. For example, different home or startingpositions of patient table 602 for a child, a head, an adult, and anobese patient may be preset and selected when desired by the operator.Moreover, subject contour information facilitates improving imagereconstruction. For example, the position encoders may transmit gammacamera location information to an image, reconstruction method such thatpositional errors may be reduced during reconstruction.

It is contemplated that the benefits of the various embodiments of thepresent invention accrue to all imaging systems, such as, for example,but not limited to, nuclear medicine imaging systems, PET, SPECT anddual-modality imaging systems.

The above-described embodiments of automatic body-contouring imagingsystems provide a cost-effective and reliable means for examining apatient. More specifically, the imaging system includes a plurality ofgamma cameras each having multiple degrees of freedom of movement, suchthat, during a scan, the gamma cameras may be automatically controlledto contour the body of a patient or subject to reduce the distancebetween the region of interest and the gamma camera sensitive face. As aresult, an imaging system is provided that facilitates improving theresolution of the gamma cameras.

Exemplary embodiments of automatic body-contouring imaging systems aredescribed above in detail. The automatic body-contouring imaging systemcomponents illustrated are not limited to the specific embodimentsdescribed herein, but rather, components of each automaticbody-contouring imaging system may be utilized independently andseparately from other components described herein. For example, theautomatic body-contouring imaging system components described above mayalso be used in combination with other imaging systems.

A technical effect of the systems and methods described herein includesfacilitating minimizing the distance between an organ of interest and animaging system detector during an automatic imaging scan of a subject,and therefore facilitating reducing operator input to the scanningprocedure and reducing the time necessary to perform a scan whileimproving the resolution of the imaging system.

While the invention has been described in terms of various specificembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theclaims.

1. A method of imaging a patient using an imaging system, said methodcomprising: rotating a detector about a patient; detecting apredetermined distance of the detector from the patient; andautomatically moving the detector in a lateral direction and atranslational direction to be within a predetermined range of distancefrom the patient based on the detected distance.
 2. A method inaccordance with claim 1 wherein rotating a detector about a patientcomprises at least one of rotating the detector continuously about thepatient and rotating the detector incrementally about the patient.
 3. Amethod in accordance with claim 1 wherein rotating a detector about apatient comprises rotating two detectors that are oriented parallel withrespect to each other and positioned diametrically opposed with respectto each other about a longitudinal axis of the imaging system.
 4. Amethod in accordance with claim 1 wherein rotating a detector about apatient comprises rotating two detectors that are substantiallyorthogonally oriented with respect to each other about a longitudinalaxis of the imaging system.
 5. A method in accordance with claim 1wherein each detector comprises a proximity sensor system that includesat least one of a near proximity sensor, a far proximity sensor, and asafety switch, and wherein detecting a proximity of the detector to thepatient comprises: transmitting a first signal representative of a farproximity condition when the near proximity sensor and the far proximitysensor do not detect the patient; transmitting a second signalrepresentative of an OK proximity status when the near proximity sensordoes not detect the patient and the far proximity sensor does detect thepatient; transmitting a third signal representative of a near proximitycondition when the near proximity sensor detects the patient and the farproximity sensor detects the patient; and transmitting a fourth signalrepresentative of an error condition when at least one of the nearproximity sensor does not detect the patient and the far proximitysensor does detect the patient, and the safety switch detects thepatient
 6. A method in accordance with claim 1 wherein the imagingsystem includes a gantry circumscribing a patient bore, the gantryincluding a transaxial movement assembly to position the detector to anyposition in a plane perpendicular to a longitudinal axis of the patientbore, and wherein rotating a detector about a patient comprises:automatically moving the detector transaxially away from the patientwhen a near proximity sensor does detect the patient; automaticallymoving the detector transaxially toward the patient when a far proximitysensor does not detect the patient; and automatically stopping movementof the transaxial movement assembly when a safety switch detects thepatient.
 7. A method of imaging a patient using a automaticbody-contouring imaging system, said method comprising: rotating adetector about a longitudinal axis of a patient viewing area; sensing adistance range between the detector and at least one of an object thatis proximate the viewing area and the patient; and moving the detectorin at least at least a lateral direction above or below a longitudinalaxis in a y-plane and independently translating the detectorhorizontally about a longitudinal axis in a x-plane using the detecteddistance range, such that a face of the detector circumscribes thepatient for a predetermined angular displacement at a substantiallyuniform distance between a face of the detector and the patient.
 8. Amethod in accordance with claim 7 further comprising displacing thepatient relative to the longitudinal axis to maintain the substantiallyuniform distance.
 9. A method in accordance with claim 7 whereinrotating a detector about a longitudinal axis of a patient viewing areacomprises rotating the detector at least one of continuously androtating the detector in predetermined angular increments.
 10. A methodin accordance with claim 9 wherein rotating a detector in predeterminedangular increments about a longitudinal axis of a patient viewing areacomprises rotating the detector in increments of between about onedegree and about four degrees.
 11. A method in accordance with claim 7wherein rotating a detector about a longitudinal axis of a patientviewing area comprises rotating two detectors substantiallydiametrically opposed with respect to each other across the patientviewing area.
 12. A method in accordance with claim 7 wherein rotating adetector about a longitudinal axis of a patient viewing area comprisesrotating two detectors substantially orthogonally oriented and adjacentwith respect to each other.
 13. A method in accordance with claim 7wherein sensing a distance range between the detector and at least oneof an object that is proximate the viewing area and the patientcomprises sensing at least one of a near proximity distance and a farproximity distance between a face of the detector and the patient.
 14. Amethod in accordance with claim 7 wherein a distance between a nearproximity distance and a far proximity distance defines a substantiallyuniform distance between a face of the detector and the patient andwherein rotating a detector about a longitudinal axis of a patientviewing area comprises controlling a transaxial movement of the detectorsuch that the detector circumscribes the patient at a substantiallyuniform distance.
 15. An imaging system for performing automaticbody-contouring, said system comprising: a gantry with a patient boretherethrough; a rotor rotatably coupled to said gantry, said rotorconfigured to rotate about a longitudinal axis of said bore, said rotorcomprising: a transaxial movement assembly coupled to said rotor, saidtransaxial assembly configured to move at least one detector in at leastone of a lateral out direction, a lateral in direction, a radial outdirection, and a radial in direction with respect to said rotor; and atleast one detector revolvably coupled to said transaxial movementassembly, each of said at least one detector configured to revolve aboutan axis that is parallel to said longitudinal axis of said bore, saidtransaxial movement assembly configured to translate each of said atleast one detector in a transverse plane of rotation of the at least onedetector.
 16. An imaging system in accordance with claim 15 wherein saidtransaxial movement assembly comprises: a lateral translation membercoupled to said rotor, said lateral translation member configured tomove in a first axis that is orthogonal to the longitudinal axis, and aradial translation member coupled to said rotor, said radial translationmember configured to move in a second axis that is orthogonal to thelongitudinal axis and the first axis.
 17. An imaging system inaccordance with claim 15 further comprising a patient table configuredto move in a table up direction and a table down direction, said tableup direction opposite said table down direction.
 18. An imaging systemin accordance with claim 16 wherein said lateral translation member isconfigured to translate said at least one detector in a lateral outdirection with respect to said rotor and a lateral in direction withrespect to said rotor, said lateral in direction being opposite to saidlateral out direction.
 19. An imaging system in accordance with claim 16wherein said radial translation member is configured to translate saidat least one detector in a Radial-1 out direction with respect to saidrotor and a Radial-2 in direction with respect to said rotor, saidRadial-2 in direction opposite said Radial-1 out direction.
 20. Animaging system in accordance with claim 15 wherein each said at leastone detector is configured to revolve 180 degrees with respect to saidtransaxial movement assembly.